Quadriplex. — Of a tetraploid: having four doses of a speci- 

 fied dominant gene (AAAA). 



Quadripolar Spindle. — A type of spindle with four poles 

 found in sporocytes. 



Quadrivalent. — An association of four chromosomes held 

 together by chiasmata during the period from diplotene to 

 metaphase of the first meiotic division. 



Quadruplets. — Four individuals arising from a single birth 

 whether monozygotic, dizygotic, or multizygotic. 



Quadruple Diploid. — An octoploid carrying in its somatic 

 nuclei a double set of each of four specifically distinct genoms. 



Quaternary Hybrid. — A hybrid derived from four grand- 

 parental types all of which are different. 



Quartet. — The four cells arising from a spore-mother cell. 



Quintuplets. — Five individuals arising from a single birth 

 whether monozygotic or multizygotic. 



